The phrase "a letter regarding" is correct and usable in written English.
It can be used when referring to a letter that addresses a specific topic or issue.
Example: "I received a letter regarding the upcoming changes to the policy."
Alternatives: "a letter about" or "a letter concerning".
So his father sends the head a letter regarding this.
He has won a default judgment against Wikimedia for Mr. Lauber in a German court, and last month sent the foundation a letter regarding Mr. Werlé, whose case against Wikimedia is pending.
Then after a few days absence he returned and told me that the State Department had examined the papers and is going to address me a letter regarding the matter shortly.
On March 18, he said, Obama briefed congressional leadership on the mission he had in mind, and followed up with a letter regarding the commencement of the military operations.
In a letter regarding operatives in Yemen, he urges that "it would be nice to remind our brothers in the regions to be patient and deliberate" and not anger local authorities.
In a closed session on May 17, hours before the injunction vote, the City Council unanimously voted to send Ms. Quan a letter regarding the limits of Mr. Siegel's authority.
Paul Jacobson, another plaintiff in the case, received a similar letter regarding a 2015 CC R-Line sedan that he bought in March 2016.
On November 12 , 2013 OPDP sent Duchesnay an Untitled Letter regarding a letter announcing the approval of DICLEGIS.
We sent an official letter regarding an annual health examination and this program for the resident aged = 18 at first.
The departmental responsible professional distributed a closed envelope containing the questionnaire, an information letter regarding the survey and a reply envelope to the patient, and then collected the reply envelope containing the questionnaire when the patient had responded.
In a 1987 letter regarding the Rev. Michael Baker, who had also been sent for treatment in New Mexico after admitting that he had abused young boys, Msgr.
